Excitation-Deexcitation of N₂⁺ (B²Σ_u⁺, v = 0) Rotational states in a Diffuse Plasma

Extract

While sharply different rotational temperature for the lower and higher rotational states of H₂ have been observed in astrophysical situations, studies on heavier molecules are less encountered. We report here results of plasma spectroscopic studies on the nitrogen system where the FNS bands (0,0) and (0,1) show much distinctive ‘two-temperature’ phenomena, the departure from the high rotational temperature part (840 ± 50°K and 920 ± 30°K respectively) being perceptible at N' (N' + 1) ≅ 160. the experimental system is an electron beam sustained magnetoplasma at 5 × 10⁻³ torr, with kT_e ≅ 1.5 eV and n_e ≅ 4 × 10¹⁰ cm⁻³ obtained from in situ measurements of plasma parameters. Relative excitation-deexcitation rates of the N₂⁺ B²Σ_u⁺ rotational states and also in relation to those of H₂ are discussed.